linux/ipc/mq_sysctl.c
Joel Granados bff97cf11b sysctl: Add a size arg to __register_sysctl_table
We make these changes in order to prepare __register_sysctl_table and
its callers for when we remove the sentinel element (empty element at
the end of ctl_table arrays). We don't actually remove any sentinels in
this commit, but we *do* make sure to use ARRAY_SIZE so the table_size
is available when the removal occurs.

We add a table_size argument to __register_sysctl_table and adjust
callers, all of which pass ctl_table pointers and need an explicit call
to ARRAY_SIZE. We implement a size calculation in register_net_sysctl in
order to forward the size of the array pointer received from the network
register calls.

The new table_size argument does not yet have any effect in the
init_header call which is still dependent on the sentinel's presence.
table_size *does* however drive the `kzalloc` allocation in
__register_sysctl_table with no adverse effects as the allocated memory
is either one element greater than the calculated ctl_table array (for
the calls in ipc_sysctl.c, mq_sysctl.c and ucount.c) or the exact size
of the calculated ctl_table array (for the call from sysctl_net.c and
register_sysctl). This approach will allows us to "just" remove the
sentinel without further changes to __register_sysctl_table as
table_size will represent the exact size for all the callers at that
point.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-08-15 15:26:17 -07:00

134 lines
3.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2007 IBM Corporation
*
* Author: Cedric Le Goater <clg@fr.ibm.com>
*/
#include <linux/nsproxy.h>
#include <linux/ipc_namespace.h>
#include <linux/sysctl.h>
#include <linux/stat.h>
#include <linux/capability.h>
#include <linux/slab.h>
static int msg_max_limit_min = MIN_MSGMAX;
static int msg_max_limit_max = HARD_MSGMAX;
static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
static int msg_maxsize_limit_max = HARD_MSGSIZEMAX;
static struct ctl_table mq_sysctls[] = {
{
.procname = "queues_max",
.data = &init_ipc_ns.mq_queues_max,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "msg_max",
.data = &init_ipc_ns.mq_msg_max,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &msg_max_limit_min,
.extra2 = &msg_max_limit_max,
},
{
.procname = "msgsize_max",
.data = &init_ipc_ns.mq_msgsize_max,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &msg_maxsize_limit_min,
.extra2 = &msg_maxsize_limit_max,
},
{
.procname = "msg_default",
.data = &init_ipc_ns.mq_msg_default,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &msg_max_limit_min,
.extra2 = &msg_max_limit_max,
},
{
.procname = "msgsize_default",
.data = &init_ipc_ns.mq_msgsize_default,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &msg_maxsize_limit_min,
.extra2 = &msg_maxsize_limit_max,
},
{}
};
static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
{
return &current->nsproxy->ipc_ns->mq_set;
}
static int set_is_seen(struct ctl_table_set *set)
{
return &current->nsproxy->ipc_ns->mq_set == set;
}
static struct ctl_table_root set_root = {
.lookup = set_lookup,
};
bool setup_mq_sysctls(struct ipc_namespace *ns)
{
struct ctl_table *tbl;
setup_sysctl_set(&ns->mq_set, &set_root, set_is_seen);
tbl = kmemdup(mq_sysctls, sizeof(mq_sysctls), GFP_KERNEL);
if (tbl) {
int i;
for (i = 0; i < ARRAY_SIZE(mq_sysctls); i++) {
if (tbl[i].data == &init_ipc_ns.mq_queues_max)
tbl[i].data = &ns->mq_queues_max;
else if (tbl[i].data == &init_ipc_ns.mq_msg_max)
tbl[i].data = &ns->mq_msg_max;
else if (tbl[i].data == &init_ipc_ns.mq_msgsize_max)
tbl[i].data = &ns->mq_msgsize_max;
else if (tbl[i].data == &init_ipc_ns.mq_msg_default)
tbl[i].data = &ns->mq_msg_default;
else if (tbl[i].data == &init_ipc_ns.mq_msgsize_default)
tbl[i].data = &ns->mq_msgsize_default;
else
tbl[i].data = NULL;
}
ns->mq_sysctls = __register_sysctl_table(&ns->mq_set,
"fs/mqueue", tbl,
ARRAY_SIZE(mq_sysctls));
}
if (!ns->mq_sysctls) {
kfree(tbl);
retire_sysctl_set(&ns->mq_set);
return false;
}
return true;
}
void retire_mq_sysctls(struct ipc_namespace *ns)
{
struct ctl_table *tbl;
tbl = ns->mq_sysctls->ctl_table_arg;
unregister_sysctl_table(ns->mq_sysctls);
retire_sysctl_set(&ns->mq_set);
kfree(tbl);
}